/*
 * Copyright 2007 Rob Nielsen
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * 	http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.googlecode.proxymatic.core.handlers.method;

import com.googlecode.proxymatic.core.BuildtimeContext;
import com.googlecode.proxymatic.core.MethodHandler;
import com.googlecode.proxymatic.core.MethodInvoker;
import com.googlecode.proxymatic.core.ProxyBuilder;
import com.googlecode.proxymatic.core.util.ReflectUtil;

import java.lang.reflect.Method;

public class EquivalentInterfaceMethodHandler implements MethodHandler {

    public MethodInvoker getInvoker(Method method, BuildtimeContext context, ProxyBuilder proxyBuilder) {
        int index = 0;
        for (Class implementationClass : context.getImplementationClasses()) {
            Method[] methods = ReflectUtil.getMethodsWithName(implementationClass, method.getName());
            for (int i = 0; i < methods.length; i++) {
                Method destinationMethod = methods[i];
                if (parametersAreEquivalent(method, destinationMethod) &&
                        returnTypesAreEquivalent(method, destinationMethod) &&
                        context.isImplementationAvailableAtRuntime() != ReflectUtil.isStatic(destinationMethod)) {
                    return new PassthroughMethodInvoker(destinationMethod, index);
                }
            }
            index++;
        }
        return NOT_HANDLED;
    }

    private boolean returnTypesAreEquivalent(Method method, Method destinationMethod) {
        return method.getReturnType().isAssignableFrom(destinationMethod.getReturnType());
    }

    private boolean parametersAreEquivalent(Method method, Method destinationMethod) {
        Class[] targetParameters = method.getParameterTypes();
        Class[] destinationParameters = destinationMethod.getParameterTypes();
        if (destinationParameters.length != targetParameters.length) {
            return false;
        }
        for (int j = 0; j < destinationParameters.length; j++) {
            if (!destinationParameters[j].isAssignableFrom(targetParameters[j])) {
                return false;
            }
        }
        return true;
    }
}
